Electric switch



Dec. 3, 1929. c. D. AINSWORTH ELECTRIC SWITCH Filed Nov. 6, 1923 Patented Dec. 3, 1929 UNETED STATES PATENT CHESTER D. AINSWORTI-I, OF WOLLASTON, NCASSACHUSETTS, ASSIGNOR, BY MESIIE ASSIGNMENTS, T0 CONDIT ELECTRICAL MANUFACTURING CORIEORATION, 0F BOS- TON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS ELECTRIC SWITCH Application filed November his invention relates to electric switches and particularly to oil-immersed electric switches.

An oil-immersed electric switch is usually provided with a movable switch-member, which switch-member includes an insulating rod, to the lower end of which the brushmember is secured. A metal switch rod or, at least, some metal member, is attached to the upper end of said insulating rod, and serves to connect it with the switch-operating mechanism. The insulating roe serves the purpose of insulating the brush-member from the switch-mechanism.

The switch-mechanism is arranged to force the brush-member with considerable pressure against the stationary switch-members, for the purpose of providing good electrical contact therebetween and, consequently, considerable stress is placed upon the insulating rod and its cnd-connections and the end connections may be displaced on or from the insulating rod.

An object of this invention is an improved construction of movable switch-men'iber and, especially, an improved manner of securing the end-connection to the insulating roe, whereby the movable switch member is well adapted to resist the forces acting upon it.

A further object is generally to improve the construction and operation of electric switches.

Fig. 1 is a partia sectional elevation of an electric switch embodying tne invention.

Fig. 2 is an elevation, partly in section, of a brush-supporting rod embodying the invcntion.

Fig. 3 is a sectional detail through the upper end-connecti m of Fig. 2.

Fig. 1 is a section along line l l of Fig. 2.

Fig. 5 is a plan view of the upper end of the insulating rod and illustrating more particularly the washer-locking slot therein.

Fig. 6 is a plan view of a washer adapted to be received on the upper end of the insulating rod.

Fig. 7 is a section along line 'l'7 of Fig. 2.

Fig. 8 is an elevation of one of the members of the brush-supporting members and 6, 1923. Serial No. 673,193.

illustrating more particularly the tapercr recess and rib in said recess.

As here shown, the electric switch to which this invention is applied, but to which it is not necessarily limited, includes the stationary switch-members 10 and the movable switch-member, which member includes the bridging, or brush, member 11. Said brushmember is or may be secured to the lower end of an insulating red 12, usually of a hard wood, and is adapted to be moved upwardly into forcible engagement with the stationary switch member A metal switch rod 13, usually smaller in diameter than said insulating rod 12, is attached to the upper end ot said insulating rod; and the upper end of said metal rod is or may be secured to suitable switch-operating mechanism 1 In accordance with this invention, improved means are provided to secure said brush-member 11 and rod 13 to said insulating rod against the tensional forces tending to separate them; and also against compressional forces tending to separate them, as in a switch of theup-brealr type. To this end, said insulating rod 12 may be formed of substantially uniform diameter throughout its extent, except at the upper end thereof, where it is formed or provided with an enlarged head 15, the side-wall 16 of which tapers inwardly and downwardly toward the body of the rod from the upper end thereof. An upper end-connector 17 is adapted to be received on said head whereby to provide attaching-means for the metal rod 13. Said end-connector is or may be approximately cylindrical in form and is or may be formed with an internal passage therethrough. The lower end of said passage may be formed or provided with an internal taper 18, which taper extends downwardly and inwardly and is adapted to conform with and seat against the tapered side-wall 16 of the enlarged head of said insulating rod. Said internal taper is or may be approximately co-extensive with the length of said tapered side-wall 16. The relative dimensions of said end-connector are or may be such that said connector may be passed over the insulating rod, from the lower end there of, to a seating position against the enlarged head of said rod and, preferably, although not necessarily, extend above the upper end of said rod. It is apparent that a force acting between said end-connector and rod to pull said connector upwardly over the enlarged head serves only to effect a more secure engagement between said rod and connector.

Means are or may be provided to force said end-connector into secure enegagement with the enlarged head of said rod and, for this purpose, the upper end of the internal passage through said end-connector may be formed or provided with the internal screw threads 19 and said passage, at said screwthreads, is preferably somewhat greater in diameter than the diameter of the upper end of the tapered portion of said passage, whereby to permit said end-connector to be passed freely over said insulating rod to a seating position therewith. A pressure-applying member as the externally screw-threaded plug 20, is adapted to be received in the threaded portion of said connector, when said connector is in seating position on the insulating rod, and exert a pressure on the upper end of said rod, whereby to draw the connector firmly against and retain it in position on the enlarged head thereof. A lockwasher 21, or other suitable lockingmeans, may be interposed between the lower end of said plug and the upper end of said rod, whereby to secure the parts together against unintentional displacement. Preferably a metal washer or cap-plate 22 is interposed between said lock-washer 21 and the upper end of the insulating rod and against which said lockovasher is adapted to bear, thereby to protect the insulating rod against the action of said lock washer. Said capplate 22 is preferably secured to the end of said insulating rod against rotation thereon and, for this purpose, a slot 23 may be formed in the end of said rod and said washer may be formed with the struck out and depending tongue or projection 24 adapted to enter said slot and bear against the side-walls thereof. The upper end 25 of said plug may be provided with suitable wrench-engaging means, whereby the plug may readily be screwed forcibly into the end-connector.

Positive means may be provided to prevent the end-connector from rotating in engagement with the insulating rod, and said means may comprise longitudinal ribs 26 formed or provided in the tapered portion of the passage through the end-connector. Said ribs extend into said passage and are adapted to bite into the enlarged head of the insulating rod 12, as said end-connector is forced into position thereon, and thereby lock said connector positively against angular rotation on said rod.

The metal switch-rod 13 may be screwthreaded into the upper end 25 of said plug 20 and, in addition, may be fixed permanently in engagement therewith by suitable means as the pin 28, which pin may pass through said rod and the upper end of said plug.

As thus arranged, said switch and insulating rod may be secured fixedly together to resist forces acting in both directions along the axes thereof tending to separate them. A tensional force acts to wedge said endconnector all the more firmly into engagement with the insulating rod and a compressional force serves to press the plug 20 with increased effect against the upper end or abutment section of said insulating rod.

The lower end of said insulating rod 12 is or may be formed or provided to receive the brush-member 11 and for this purpose, may be formed or provided with the reduced and tapered end-portion 30, which is largest in diameter at the extreme lower end of the rod and which converges inwardly and upward ly and has its smallest diameter at the shoulder or abutment section 31, at which shoulder it is smaller than the rod. The brush member may include the complemental brush-supporting members 32 and 33, which members may comprise lower end-connections for said insulating rod. Said brushsupporting members may have the feet 34 and 35 to which the brush-member may be secured. Said supporting members may also have the vertical extensions 36 and 37 which are formed, when said members are clamped in position about the insulating rod 12, to provide an internal passage 38 therethrough; and said passage is shaped to conform to the tapered end-portion 30 of said rod 12 and, consequently, said passage is smallest at the upper end and largest at the lower end thereof. Said complemental brush-supporting members may be clamped about the lower end of said rod 12 by suitable means as the bolts 39. As thus arranged, the supporting members, by means of the tapered connection between them and the rod 12 are retained securely on said rod against tensional force acting between said members and said rod. Said members, also, are arranged to be disposed beneath and bear against the shoulder 31 of said rod, whereby to resist displacement in an upward direction by reason of a compressional force acting between said members and said rod. The lower end of said insulating rod may be substantially flush with the feet 3 1 and 35 of said supporting members and therefore bear directly against the brush member 11, whereby additionally to resist displacement due to a compressional force.

Said supporting members may be formed or provided with ribs 42, Fig. 7, which ribs may be disposed transversely Within the tapered recesses thereof, and are arranged to bite into the tapered end-portion 30 of the insulating rod, whereby to secure the supporting members the more firmly in position on said rod.

The structure may be otherwise modified without departing from the spirit of the invention.

I claim:

1. An insulating rod adapted to be placed under mechanical tension and compression and having its end-portions provided with oppositely-directed tapered sections and also with abutment-sections, one of which is at the large end of one tapered section and the other of which is at the small end of the other tapered section, and end-connectors having tapered sections conformed with and seated on the tapered sections of said rod and also having abutment-sections disposed in abutting relation with the abutment-sec tions of said rod, said co-operating abutmentsections serving to transmit a compressional force and said tapered sections serving to ransmit a tensional force, ietween said con nectors and through said rod.

2. A movable switch member for an elec tric switch including an insulating rod provided at one end with an enlarged downwardly and inwardly tapering head, an enc connector having a tapered recess in which said tapered head is wedged, means to lock said connector against rotation on said rod, and a plug screw-threaded in said end-connector above and in pressure-applying relation with said enlarged head.

A movable switch member for an electric switch including an insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardly toward the body of the rod, an end-connector having a passage therethrough the lower portion or" which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, means to lock said connector against rotation on said roe, an externally screw-threaded plug received in the screw-threaded portion of said passage above and in pressure-applying relation with the enlarged head of said rod, and a switch-rod fixed to said plug.

l. A movable switch member for an electric switch including an insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardly toward the body of the rod, an end-connector having a passage therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passageis internally screw-threaded, means to lock said connector against rotation on said rod, an externally screw-threaded plug receved in the screw-threaded portion of said passage above and in pressure-applying relation with the enlarged head of said rod,

and loclting means including a lock-washer interposed between said plugand the end of said rod.

5. A movable switch member for an elTectricswitch including an insulating rod provided at one end w1th an enlarged head, said head having a side wall which tapers 1nwardly and downwardly toward the body of the rod, an end-connector having a passage therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, means to lock said rod against angular movement in' said connector, and externally screwthreaded plug received in the screw-threaded portion of said passage above and. in pressure-applying relation with the enlarged head of said rod, a metal cap-plate disposed over the end of said rod: and a lock-washer on said plate beneath said plug'and engaging both.

(3. A movable switch member for an electric switch including an: insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardly, toward the body of. the rod, an end-connector having a passage. therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, an externally sereW-threaded plug received in the screw-threaded portion of said passage above and inpressure-applying relation with the enlarged head of said rod, and a metal capplate disposed over the end of said rod and beneath said plug, said cap-plate having a depending tongue, and said rod having a slot in the end thereof in which said tongue is received.

7. A movable switch member for an electric switch including an insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardl toward the body of the rod, an end-connector having a passage therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, an externally screw-threaded plug received in the screw-threaded portion of said passage above and in pressure-applying relation with the enlarged head of said rod, and a metal capplate disposed over the end of said rod and beneath said plug, and means to lock said cap-plate to the end of said rod against angular movement thereon.

8. A movable switch member for an electric switch including an insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardly toward the body of the rod, an end-connector having a passage therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, an externally screw-threaded plug secured in the screw-threaded portion of said passage above and in pressure-applying relation with the enlarged head of said rod, a metal capplate disposed on the end of said rod and beneath said plug, a lock-washer interposed between said plug and cap-plate, and means to hold said cap-plate on said rod against rotation thereon.

9. A movable switch member for an electric switch including an insulating rod provided at one end with an enlarged head, said head having a side wall which tapers inwardly and downwardly toward the body of theirod, an end-connection having a passage therethrough, the lower portion of which passage is tapered to receive the tapered head of said rod, and the upper portion of which passage is internally screw-threaded, an externally screw-threaded plug received in the screw-threaded portion of said passage above and in pressure-applying relation with the enlarged head of said rod, a metal capplate disposed on the end of said rod and be neath said plug, a lock-washer interposed between said plug andcap-plate, and means to hold said cap-plate on said rod against rotation thereon, comprising a tongue struckout of said cap-plate and entered in a slot in r the end of said rod.

10. A movable switch member for an electric switch including an insulating rod having a tapered end-portion, an end-connector received on the tapered end-portion of said rod and having a tapered recess conformed with and in which the tapered end-portion of. said rod is received, said end-connector having a rib which projects into said recess and bears into said rod, and anattachingmember secured to said end-connector and means to lock said attaching member and end-connector against relative rotation.

In testimony whereof, I have signed my name to this specification.

CHESTER D. AINSWORTH. 

